| Backgound Pulmonary arterial hypertension is a rare pulmonary vascular disease characterized by the small to mid-sized pulmonary artery remodeling with a poor prognosis.Pulmonary arterial hypertension is associated with the activation of sympathetic nerve system,but the exact mechanism remains to be fully understood.Objective To evaluate the level of norepinephrine and neuropeptide Y at the pulmonary sympathetic vascular junction and the mechanism in pulmonary vascular remodeling in pulmonary arterial hypertension model induced by monocrotaline.Methods A randomization method was used to group 20 rats at the age of 6-8 weeks :control group(n=9)and monocrotaline induced pulmonary arterial hypertension group(n=11).Right ventricular pressure measured transabdominally via an intravenous catheter after 6 weeks.The right ventricle hypertrophy index was calculated by weighing the ventricle and septum.Hematoxylin & eosin and immunofluorescence were performed to stain tissue paraffin sections.Plasma norepinephrine and neuropeptide Y levels were analyzed by ELISA kits.Pulmonary artery smooth muscle cells were obtained from SD rat pulmonary artery tissue for primary culture.Western Blot was used to analyze the expression of relative proteins.Experimental Methods such as CCK8,flow cytometry and Western Blot were used to analyze the proliferation ability of pulmonary artery smooth muscle cells,and the cell wound scratch assay was used to evaluate the ability of migration.Results1.Compared to Control group,the RVSP(13.3 ± 2.1 mm Hg vs.33.2 ± 5.9 mm Hg,P < 0.01),RVDP(3.6 ± 2.7mm Hg vs.16.7 ± 5.0mm Hg,P < 0.01),m PAP(6.6±1.8mmhg vs.22.2±1.5mm Hg,P < 0.01)and RVHI(29.4% ± 5.3% vs.68.0% ±13.1%,P < 0.01)were significantly increased in the MCT-PAH group.2.Compared to Control group,Pulmonary vascular lesions were observed including concentric thickening of distal small arteries,thickening of the pulmonary arteriolar significant lumen narrowing with an increased MWT%(38.5% ± 11.8% vs.64.5% ± 8.4%,P < 0.01),VWA(56.4% ± 9.4% vs.85.6% ± 5.9%,P < 0.01)and the expression of Ki67(P < 0.05)in the MCT-PAH group.3.Compared to Control group,MCT-PAH group showed increased plasma NE(100.3 ± 9.0nmol/L vs.124.7 ± 20.7nmol/L,P < 0.01)and NPY(914.2 ±181.5ng/L vs.1116.0 ± 138.9ng/L,P < 0.05)levels,increased the expressions of TH(P < 0.01)and NPY(P < 0.01)both in lung tissue and around the distal small pulmonary arteries(all P < 0.05),and the expressions of α1-AR and NPY1 R were also increased.4.The cell viability of PASMCs was highest in the NE(P < 0.05)and NPY(P <0.01)groups at a concentration of 100 nmol/L.The proliferation index and division index of CFSE-labeled PASMCs were significantly increased in the NE and NPY group,and the expression of PCNA and Cyclin E1 was also increased in the NE group.5.NE and NPY significantly accelerate scratch wound closure of PASMCs compared to the control group.Conclusion1.the expressions of NE,NPY were elevated in the plasma,lung tissue and pulmonary sympathetic vascular junctions.It may be related to the overactivation of both the systemic and local pulmonary sympathetic nerve system.2.NE and NPY are able to promote the proliferation and migration of PASMCs.NE and NPY may be involved in the pulmonary vasculature remodeling in PAH. |
